sweep: Remove publishing last-tx logic.

We remove the publishing of the last published sweep tx during the
startup of the sweeper. This republishing can lead to situations
where funds of the default wallet might be locked for neutrino
backend clients.
Moreover all related tests are removed as well.

sweep/store.go

@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"encoding/binary"
 	"errors"
-	"fmt"
 
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/wire"
@@ -12,15 +11,6 @@ import (
 )
 
 var (
-	// lastTxBucketKey is the key that points to a bucket containing a
-	// single item storing the last published tx.
-	//
-	// maps: lastTxKey -> serialized_tx
-	lastTxBucketKey = []byte("sweeper-last-tx")
-
-	// lastTxKey is the fixed key under which the serialized tx is stored.
-	lastTxKey = []byte("last-tx")
-
 	// txHashesBucketKey is the key that points to a bucket containing the
 	// hashes of all sweep txes that were published successfully.
 	//
@@ -52,10 +42,6 @@ type SweeperStore interface {
 	// NotifyPublishTx signals that we are about to publish a tx.
 	NotifyPublishTx(*wire.MsgTx) error
 
-	// GetLastPublishedTx returns the last tx that we called NotifyPublishTx
-	// for.
-	GetLastPublishedTx() (*wire.MsgTx, error)
-
 	// ListSweeps lists all the sweeps we have successfully published.
 	ListSweeps() ([]chainhash.Hash, error)
 }
@@ -69,13 +55,6 @@ func NewSweeperStore(db kvdb.Backend, chainHash *chainhash.Hash) (
 	SweeperStore, error) {
 
 	err := kvdb.Update(db, func(tx kvdb.RwTx) error {
-		_, err := tx.CreateTopLevelBucket(
-			lastTxBucketKey,
-		)
-		if err != nil {
-			return err
-		}
-
 		if tx.ReadWriteBucket(txHashesBucketKey) != nil {
 			return nil
 		}
@@ -171,64 +150,18 @@ func migrateTxHashes(tx kvdb.RwTx, txHashesBucket kvdb.RwBucket,
 // NotifyPublishTx signals that we are about to publish a tx.
 func (s *sweeperStore) NotifyPublishTx(sweepTx *wire.MsgTx) error {
 	return kvdb.Update(s.db, func(tx kvdb.RwTx) error {
-		lastTxBucket := tx.ReadWriteBucket(lastTxBucketKey)
-		if lastTxBucket == nil {
-			return errors.New("last tx bucket does not exist")
-		}
 
 		txHashesBucket := tx.ReadWriteBucket(txHashesBucketKey)
 		if txHashesBucket == nil {
 			return errNoTxHashesBucket
 		}
 
-		var b bytes.Buffer
-		if err := sweepTx.Serialize(&b); err != nil {
-			return err
-		}
-
-		if err := lastTxBucket.Put(lastTxKey, b.Bytes()); err != nil {
-			return err
-		}
-
 		hash := sweepTx.TxHash()
 
 		return txHashesBucket.Put(hash[:], []byte{})
 	}, func() {})
 }
 
-// GetLastPublishedTx returns the last tx that we called NotifyPublishTx
-// for.
-func (s *sweeperStore) GetLastPublishedTx() (*wire.MsgTx, error) {
-	var sweepTx *wire.MsgTx
-
-	err := kvdb.View(s.db, func(tx kvdb.RTx) error {
-		lastTxBucket := tx.ReadBucket(lastTxBucketKey)
-		if lastTxBucket == nil {
-			return errors.New("last tx bucket does not exist")
-		}
-
-		sweepTxRaw := lastTxBucket.Get(lastTxKey)
-		if sweepTxRaw == nil {
-			return nil
-		}
-
-		sweepTx = &wire.MsgTx{}
-		txReader := bytes.NewReader(sweepTxRaw)
-		if err := sweepTx.Deserialize(txReader); err != nil {
-			return fmt.Errorf("tx deserialize: %v", err)
-		}
-
-		return nil
-	}, func() {
-		sweepTx = nil
-	})
-	if err != nil {
-		return nil, err
-	}
-
-	return sweepTx, nil
-}
-
 // IsOurTx determines whether a tx is published by us, based on its
 // hash.
 func (s *sweeperStore) IsOurTx(hash chainhash.Hash) (bool, error) {